Carburetor



* Feb. 4,-1930. H. w. LINKER-r Y 1,745,496

l l GARBURETOR Filed Au.'23, 1924 Patented Feb. 4, 1930 'UNITED STATESPATENT OFFICE HOWARD W. LUKERT, OF INDIANAEOLIS,l INDIANA, ASSIGNOR TO THE WHEELER- SGHEBLEB GABBURETOR C0., OF INDIANAPOLIS, INDIANA, A CORPORATION 0F IN- Dram. A

i cmsunnroa application mea August '23, 1924. serial No. 733,695.

In carburetors using liquid fuel, part of the atomized fuel is deposited as a liquid on the walls of the carburetor and the surfaces of any obstructions which may be in the delivery passage of the carburetor. This deposited liquid runs down` and collects in an increasing quantity as long. as the air velocity through the carburetor is below that value which will cause the collected liquid fue1`to be swept into the motor. If, after a considerable collection .of liquid fuel has formed, the

air velocity through the carburetor is increased' sufficiently, this collected fuel'is swept on intothe motor in addition to the regular supply of fuel, thus temporarily causing an excessively rich mixture, which interferes with the proper action ofthe motor and produces an uneven'rolling action frequently described as loading. Iny addition, if the air velcity through the .carburetor is not increased, the collection of liquid` fuel continues until its amount hinders the regular action of the carburetor and. gives an intermittently rich mixture with consequent ill effects.

The principal object of the present invention is to reduce this collection of liquid fuel in thebody of the carburetor'to a minimum under all operating conditions, especially in the carburetor'invented by Berry and Linkert and shown in their application Serial No. 639,191, filed- May 15, 1923. Further objects are to reintroduce the collected liquid fuel into the stream of fuel supplied by the metering device to the carburetor nozzle. and into the middle rather than the outside of the air stream through the carburetor, so that it will be least apt to strike the carburetor walls again; to do this by gravity, plus a positive air-pressure and air flow; and tolprovide an air-bleeding arrangement for the fuel nozzle to promote atomization. v l

In carrying out my invention, I-provide -a roel-returning conduit from the lowest pointof thek carburetor body, to the fuel passage for a fuel nozzle, desirably into the supply passage for the main fuel nozzle between the metering point andthe discharge end of the nozzle. The liquid fuel which is deposited upon surfaces within the carburetor Hows by gravity to the Alowest portion of said carburetor body when the air velocity is low.l The fuel thus collected does not remain as a pool at any time, butpasses through the fuelreturning conduit into the nozzle, whence it is re-discharged into the air stream. The' fuel nozzle discharges within the usual venturi, so that the pressure is lower at the nozzle `than in the carburetor body; and this differential air-pressure tends to force the liquid from the lowest point of the carburetor body into the nozzle and thence into the air stream. This same differential air-pressure causes air to be fed into the fuel stream, which air as-- sists -in the atomization of the fuel as it is dlscharged from the nozzle within the venturi and also assist in carrying deposited fuel into y the fuel stream.

Although my invention is applicable to car` buretors of various designs,'it is of especial value as an improvement on the aforesaid carburetor invented by Berry and Linkert, in connection with which carburetor my invention is shown'in the accompanying drawing, as that illustrates my invention in the preferred form. I n this carburetor, it is most important to prevent the collection of deposited liquid fu l under all conditions, and to insure asthorou h atomization of the fuel as possible. i

The accompanying drawing illustrates my invention: Fig. 1 is a vertical central section, substantially on the line' 1-1 of Fig. 2, through a carburetor embodying my invention; Fig. 2 is a vertical section on the line rtal viewcorresponding to the lower` left-hand part of Fig. 1, showing the fuel control, fuelreturn, and fuel-dischargeanechanism, being taken substantially on the liIr'eS-S of Fig. 4; and Fig. 4 is a'tran sverse section, still further enlarged, on the-line 4-4 of Fig. 3.

In the carburetor which I have shown, the main body 1() of t e carburetorhas within it a main chamber 11, into which a enturi 12 projects upwardly, desirably in line with the carburetor-discharge opening 13. The discharge end of a fuel nozzle 15 is located in the vicinity of the choke of the venturi 12. The venturi 12 receives primary air through the primary air inlet 14.. Secondary air 1s ad? mitted into the chamber 11 through a sec-v ondary-air opening 16, the elfectivf size of which is controlled by a spring-loaded secondary-air valve 17. Movements of this secondary-air valve are controlled by the mechap nism in a dash-pot 18. This dash-pot mechanism is explained in detail in the aforesaid Berry and Linkert application. f

The actionof the dash-pot mechanism is o such that pistonv 49, check disc 45, and the .disc 46 act `together as a solid piston inthe cylinder 52, damping out all fluttering', when the air-valve 17 is subjected to slight downward impulses, which occur, for instance,-

when the carburetor is delivering with a wideopen throttle to a motor running at low speeds. Liquid fuel inthe float chamber v covers the top of thepiston 49 atv all-times and fills the cylinder 52. The piston 49 is slid- 2'9 ably mounted onthe steml 50, and the check disc 45 is rigidly fastened to the stem. Under a strong .impulse-upon t-he air-valve 17, such Aas occurs when the throttle .is suddenly opened while the motor is idling at a high 25 speed, the spring 48which is strong enough to withstand a slight pressure, collapses,allowing the liquid in the cylinder 52 to rush rapidly through the holes 47 in the piston 49, and thus'perrrritting the air-valve to drop rapidly to its working position. The disc 46 tends tol prevent any jdownward motion of the air-valve; but allows upward motion thereof,

since it drops down to allow liquid to pass through the holes 47 in the piston 49 and' check disc into the cylinder 52.

The carburetor-discharge opening 13 is controlledby the usual throttle 19. This throttle isshown connected by a linkage 53,

to a fuel-lifting device 2O which is also described in detailin said Berry and Linkcrt application. The fuel-lifting device provides accelerating fuel when the throttle is -opened, by lifting fuel from the cylinder 54,

through the restricted passageway 55, into a measuring chamber 56, whence it flows through a metering passageway 58 to the venturi 12. The measuring chamber 56 is provided with an overflow passage `57. The fuel-lifting device gets its supply of fuel from the float chamber '25, linto which. the

lower end'of the cylinder 54 opens. The fuel is controlled by any suitable float-operated' vaive26; The lower end of a tube 27 opens downwardly into this fuel chamber 25, while the upper end of such-tube located within e5 the chamber 11. At an intermediate interior point, near its lower end, the tube 27 is provided with a valve seat 28, with which the ,A

tapered lower end of a fuel-controlling needle 29 coopera-tes forms the fuel-metering point of the carburetor. The tube 27serves as a guide for the needle 29. The fuel-controlling needle 29 is connected to the air-valve 17 by means of a proportioning lever 30, which is pivotally connected to the air-valve 17, the needle 29, and the lower end of the fulcrum lever 56, so that the fuel-controlling needle 29 receives a variably proportionate amount of the movement of the air-valve17.

.The `features which so far' have been specilically described lare all shown inthe aforesaid co-pending Berry and Linkert application.

formed in the body 10 Aofthe carburetor, vat one side of the primary-air-inlet passage 14; but it does net ll such well, so that between the inner wall `of suehwell and the outer wall Thetube 27 is located within a well 35 of thetube 27 there is an annular space'36. j

Transverse holes 37 in the tube V27 just above the valve seat 28 connect the space within such tube 27 to the annular space 36 around such tube. A- transverse passage 38 leads from the ,annular space 36 to the bottom of the fuel noz- Zle 15. The passage 38 is conveniently made by drilling through from the outsidek of the member in which such passage is formed, and then closing the outer end of such passage by an expanding cap, which may be soldered in place. The lower end of the tube 27 has a screw-mounting 39 in the floor of the well 35.l

The tube 27 is turned bodily in the well 35, by

a suitable operating mechanism 40 acting on of the tube 27 ;'so that by turning the knurledk head the tube 27 `s turned in its screw mounting to be raised or' lowered as a result of such turning. 'This feature is described` in detail in the aforesaid Berry and Linkert .application. l l

The 'upper'end of the well 35 opens into the chamber 11 at the lowest point of the floor 41 of such chamber, desirably within a sump 44; and the upper end of thetube27 projects upward out of the upper end of the well' 25. N ear its upper end, the tube 27 is guided in its movements in the well 35 by longitudinal ribs42, provdedexternally on such tube in the upper end of the well and having between them longitudinal slots 43 which .provide communication from the chamber 11 into the annular space 36.

iio

ln operation, liquid fuel isdeiposited onthe I 'ity through the 'carlniretcrisv less than a certainvalue, `thisliquid fuel lows down by incoming fuel which hasjustentered such 'annular' space 36 through the openings' 37; I

`and thismifxture' of incoming and'returned fuel is fed by the' passageway 38 into the nozinto the interior Arather than on the outside of zle 15, and thence dischargedwithi'n the venturi A12 into the center ofthe air stream passing upward through such' venturi. In. this way, the returned'fuel is re-int'roduced into 'the air stream, and this re-introduction is suchair stream; Y Y

The returnf ofthis fuel into the main fuel 'stream is caused not only byl gravity, but'by 'Haj positivev differentiall air' pressure between the sump 44 andthe discharge end of the nozj 15.1 velocities ybut the return of fuel by the sump l zle 15, therebeinganair liow produced by." I such dilferentialfair pressure from the sump 44v .through theslots 43, annular passage 36, andtransversepassage 8, into the fuel nozzle.

'Thisdii'erential air pressure is the bulkof thevv l.

difference between the pressure in the chamber-'lland the-loweredpressure at'the 'choke vply chamber,` theupper end of said well be- .ing arranged to receiveliquid which is deposited on surfaces withinthe carburetor beyond the contraction of the venturi.r l

. 2. In a'carburetor,'a mixing chamber hav- "ing a sump,.a well open to said sump to receive drainage therefrom, a `fuel chamber with which said well also communicates, a

fuel nozzle arranged to discharge within said mixing chamber and receiving its fuel from the. fuel chamber through 4said Well, and` a 4metering pin controlling passage of fuel from vthe fuel chamber to said well.

In witness whereof, I have hereunto my handaplndianapolis, Indiana, th is.'15th` v 80 set day of August, A. D. one thousand nine hun- 'dred'andtwenty-four.

HOWARD w. Lrunnn'r.

of the venturifl2 ,land insures the flow of the fuel .from the sump 44 into the annular space 36 andthence'into and from .the nozzle 15,

'and the *air flow producedby this 'differential pressure `assistsfin thusmoving this returned fuel. Moreover, this air ilow produces an air-bleeding into the fuel stream in the nozzle 15, which'air-bleeding assists. materiali in theatomiz'ing of the fuel discharged om such nozzle. This air-.bleeding, with its Vasf sistanceto atomizati'on,.1may occur at ally air i' 44'and slots 43 into the annular space 36 only 45. certain value.' By this return 'of fuel when occurs when the airvelocities are below a the air velocities are low, the'formationof-a pool-of liquid fuel in the chamber 11 isavoid-v ed', :so that theresl no such collectionoffuel to be carried overinto the motor when an'in-' crease in'air velocity occurs. .-Thus the so'- called loading of the motor by the carburetor is `effectively,- avoided.

Y Iclaim-as my invention:

1; In a carburetor, thec'ombina'tion of a v'fenturi, a 'fuel nozzle'arranged to discharge wi'thnsaidventuri, a well'open atits top' into said carburetor at a low point in the floor thereof and on the discharge side of the venturiand communicating' with said fuel lnoz- 4 zle, a. fuel-supply chamber, a tube located in said wellbut lspaced from the walls thereof,

' the interior of said tube communicating with I said well, said tube being provided with a metering communication with saidfuel-sup- 

